How can I grow vegetables and flowers in containers on my back porch?

Here are a couple of ideas... and check Gardners.com they have lots of container garden ideas that you could use for inspiration.

Is your porch wood? Will it hold several heavy containers wit soil and water? Do you have ideas for holding containers off porch surface for drainage, like either pot feet or even bricks? Does the porch get all day sun or just part of the day? These are all the questions you need to answer before picking out what will grow there. then the fun begins, get yourself down to the garden store/hardware/nursery and pick your plants or seeds.Some plants do well in deep soil, so those containers will need to be the tallest, flowers can grow in shallower boxes/pots. Don't try to do it all in one go, start with some and tweak over the Summer. Show us some before and after pix if you can..

https://www.bhg.com/gardening/vegetable/vegetables/growing-vegetables-in-containers/

I had excellent results doing tomatoes in pots last year. They get full sun under my deck. Trying full sized, roma and cherry tomatoes this year. Its a good plant to start with.